For a long time he saw nothing whatever. Then a tiny disk moved slowly into the eyepiece's field. It was barely larger than a point. Nolan moved one of the eyepiece controls. The disk enlarged. It enlarged again. A tiny red dot appeared in the center of the field of vision. As the disk enlarged, the red dot grew larger and became a tiny red circle. Nolan fumbled. He shifted the position of the instrument with a micro-control. He moved the faintly glowing disk until it was enclosed in the red circle. He enlarged.... Presently the disk was very large, and the red circle ceased to enlarge. It enclosed only a part of the disk. Nolan felt cold chills down his spine. He swallowed and asked for the angular relationship of Planet Four to Three. The skipper sent someone to find it out. But Nolan had found Planet Four before the answer came. The first disk was in some fashion a representation of Planet Three--the Earthlike world which was dead. The second was a representation of Four. There was a bright spot near the equator of Four--the equator being located by the flattening of the poles. It would be just about where a gigantic atom-bomb crater still existed. Nolan drew back and took a deep breath. "Apparently," he said unsteadily, "this eyepiece detects radioactives, converting something that I can't imagine into visible light after it's passed through a few feet of metal and a good many more of dirt. There's a red ring which makes me think of a gun-sight. And there's a trigger. Skipper, would you send half an ounce or so of ship-fuel out to space in a drone? I think we're going to have to pull this trigger." The skipper wrung his hands. He went away. And Nolan stood staring at nothing in particular, appalled and sickened by the thoughts that came to him. Presently the skipper came back and mumbled that a drone was on the way up. Nolan searched for it with the eyepiece. He found it. The sensitivity of the eyepiece was practically beyond belief. What it worked on--what it transmuted and amplified to light--was wholly beyond his imagination. The drone went four thousand miles out. Nolan absently asked for somebody to be posted out of doors, watching the sky. He got the vivid spark that was the half ounce of ship-fuel in the center of the red luminous ring. He turned his eyes away and pulled the trigger. There was no sound. There was no vibration. There was no indication in the underground room that anything at all had happened. There was only a violent flare in the eyepiece, from which Nolan had just drawn back. Someone came shouting from out of doors that there had been an intolerable flash of brilliance in the sky. A few moments later the word came that the drone control board indicated that the drone had ceased to exist. * * * * *